Color filter substrate, method for manufacturing the same, liquid crystal display panel, and electronic equipment

ABSTRACT

Each color filter  22  includes a deep-color portion  221  being superimposed on a translucent portion  211  of a reflection layer  21  and a light-color portion  222  having an optical density lower than that of the deep-color portion  221 . A light-shielding layer  23  for shielding the gaps between individual subpixels  7  from light is a laminate composed of at least a deep-color portion  221 B of a blue color filter  22 B, a deep-color portion  221 R of a red color filter  22 R, and a deep-color portion  221 G of a green color filter  22 G.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. Ser. No. 10/310,636filed Dec. 5, 2002 claiming priority to Japanese Patent Application No.2001-374040 filed Dec. 7, 2001, all incorporated herein by reference.

DETAILED DESCRIPTION OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to a color filter substrate and a methodfor manufacturing the same, and a liquid crystal display panel andelectronic equipment using the color filter substrate.

2. Description of the Related Art

Conventionally, so-called semitransparent reflective liquid crystaldisplay panels, in which the reflective display and the transmissivedisplay can be changed on an as needed basis, have been suggested. Asshown in FIG. 12, in this sort of liquid crystal display panel, areflection layer 21 including a translucent portion 211 (opening) isarranged on a second substrate 20 facing a first substrate 10 so as tohold a liquid crystal 40 therebetween. On the observation side whenviewed from the reflection layer 21, color filters 22, each beingcolored, for example, any one of red, green, and blue, are arranged. InFIG. 12, electrodes for applying a voltage to the liquid crystal 40, anorientation film for regulating the orientation condition of the liquidcrystal 40, etc., are omitted from the drawing.

Under this configuration, incident light (external light, for example,room illumination light and sunlight) from the first substrate 10 sidepasses through the first substrate 10, the liquid crystal 40, and thecolor filter 22, and reaches the surface of the reflection layer 21 asindicated by a route R1 shown in FIG. 12. Subsequently, the lightreflected at this surface passes through the color filter 22, liquidcrystal 40, and the first substrate 10, outgoes on the observation sideand, therefore, the reflective display is performed. On the other hand,incident light (for example, irradiation light by a backlight unit) fromthe second substrate 20 side passes through the second substrate 20 andthe translucent portion 211 of the reflection layer 21 as indicated by aroute R2 shown in FIG. 12. Thereafter, this light passes through thecolor filter 22, liquid crystal 40, and the first substrate 10, outgoeson the observation side and, therefore, the transmissive display isperformed.

However, regarding the conventional semitransparent reflective liquidcrystal display panel, the light visually identified by an observer inthe reflective display is the light which has passed through the colorfilter 22 twice, there and back, while the light visually identified bythe observer in the transmissive display is the light which has passedthrough the color filter 22 only once. Consequently, there has been aproblem in that the chroma in the transmissive display has become lowerthan the chroma in the reflective display. On the other hand, generally,in the reflective display, since the brightness of display is likely tobecome inadequate, it is desirable to increase the light transmittanceof the color filter 22 so as to ensure the brightness of the display.However, in such a case, the shortage of chroma in the transmissivedisplay becomes more remarkable.

The present invention was made in consideration of the aforementionedcircumstances. Accordingly, the object of the present invention is toprovide a liquid crystal display panel capable of ensuring both of thebrightness in the reflective display and the chroma in the transmissivedisplay, a color filter substrate used for this liquid crystal displaypanel and a method for manufacturing the same, and electronic equipmentusing the liquid crystal display panel.

SUMMARY OF THE INVENTION

In order to overcome the aforementioned problems, a color filtersubstrate according to the present invention is provided with asubstrate for holding a liquid crystal between the substrate and othersubstrate, a reflection layer for reflecting light which is arranged onthe aforementioned substrate and which is provided with a translucentportion for transmitting light, a plurality of color filters which arearranged on the aforementioned substrate, which are for transmittingrespective light with wavelengths corresponding to different colors, andeach of which includes a deep-color portion being superimposed on atleast the translucent portion of the aforementioned reflection layer anda light-color portion having an optical density lower than that of thedeep-color portion, and a light-shielding layer composed of a laminateof at least the deep-color portions of the aforementioned plurality ofcolor filters.

According to this color filter substrate, since the light, which reachesthe surface of the reflection layer and which is reflected at thesurface, passes through the light-color portion having a low opticaldensity, the brightness of the reflected light can be maintained at ahigh level. On the other hand, since the light, which has passed throughthe translucent portion of the reflection layer, passes through thedeep-color portion having a high optical density, the chroma of thetransmitted light can be maintained at a high level. Furthermore, sincethe light-shielding layer is composed of a laminate of the deep-colorportions having a high optical density in the color filters, anexcellent light-shielding property can be achieved.

Although the aforementioned color filter substrate is provided with areflection layer and is located on the backface side in the liquidcrystal display panel, the color filter substrate according to thepresent invention can also be used as the one located on the observationside. That is, the color filter substrate may be provided with asubstrate for holding a liquid crystal between the substrate and othersubstrate provided with a reflection layer for reflecting light, thereflection layer being provided with a translucent portion fortransmitting light, a plurality of color filters which are arranged onthe aforementioned substrate, which are for transmitting respectivelight with wavelengths corresponding to different colors, and each ofwhich includes a deep-color portion being superimposed on at least thetranslucent portion of the aforementioned reflection layer and alight-color portion having an optical density lower than that of thedeep-color portion, and a light-shielding layer composed of a laminateof at least the deep-color portions of the aforementioned plurality ofcolor filters. In this case as well, the chroma of the transmitted lightcan be maintained at a high level without loss of the brightness of thereflected light and, in addition, the light-shielding property of thelight-shielding layer can be improved.

In the color filter substrate according to the present invention, theaforementioned light-shielding layer may be composed of a laminate ofthe deep-color portions of the aforementioned plurality of color filtersand the light-color portion of at least one color filter of theaforementioned plurality of color filters. According to this, thelight-shielding property can be further improved compared with that inthe case where the light-shielding layer is composed of only thedeep-color portions of the color filters.

In order to overcome the aforementioned problems, in the presentinvention, a liquid crystal display panel including a liquid crystalbetween a first substrate and a second substrate facing each other isprovided with a reflection layer for reflecting the light incident froman observation side, the reflection layer being arranged on the secondsubstrate and being provided with a translucent portion for transmittinglight incident from the backface side upon the observation side, aplurality of color filters which are arranged on the observation sidewith respect to the aforementioned reflection layer, which are fortransmitting respective light with wavelengths corresponding todifferent colors, and each of which includes a deep-color portion beingsuperimposed on at least the translucent portion of the aforementionedreflection layer and a light-color portion having an optical densitylower than that of the deep-color portion, and a light-shielding layercomposed of a laminate of at least the deep-color portions of theaforementioned plurality of color filters.

According to this liquid crystal display panel, for the same reasons asthose described above with respect to the color filter substrate, thechroma in the transmissive display can be maintained at a high levelwithout loss of the brightness in the reflective display. In addition,since the light-shielding property of the light-shielding layer can beimproved, excellent contrast of the display can be realized. Here,“optical density” refers to the ability to make the wavelengthdistribution of light one-sided on a unit thickness of the color filterbasis. That is, when the optical density is high (large), the chroma ofthe transmitted light becomes strong, and when the optical density islow (small), the chroma of the transmitted light becomes weak.

In this liquid crystal display panel, the aforementioned plurality ofcolor filters and the aforementioned light-shielding layer may bearranged on the aforementioned second substrate. Furthermore, it is alsodesirable that the aforementioned light-shielding layer has aconfiguration composed of a laminate of the deep-color portions of theaforementioned plurality of color filters and the light-color portion ofat least one color filter of the aforementioned plurality of colorfilters. In this case, since the optical density of the light-shieldinglayer can be improved compared with that in the case where thelight-shielding layer is composed of only deep-color portions of thecolor filters, further excellent contrast of the display can beachieved.

It has been discovered that in the case where each of the aforementionedplurality of color filters transmitted light with a wavelengthcorresponding to any one of red, green, and blue, in a CIE chromaticitydiagram, the area of color reproduction region when transmissive displaywas performed while light incident from the backface side was allowed topass through the translucent portion of the aforementioned reflectionlayer was specified to be 3.5 times or more, but 5 times or less thanthe area of color reproduction region when reflective display wasperformed while light incident from the observation side was reflectedby the aforementioned reflection layer and, therefore, especiallyexcellent display quality could be achieved. Consequently, it isdesirable that the optical densities of the aforementioned deep-colorportion and the light-color portion are chosen in order to satisfy thiscondition.

In order to overcome the aforementioned problems, electronic equipmentaccording to the present invention is provided with the aforementionedliquid crystal display panel. As described above, since the chroma inthe transmissive display can be maintained at a high level without lossof the brightness in the reflective display and, in addition, excellentcontrast of the display can be achieved by the liquid crystal displaypanel according to the present invention, the liquid crystal displaypanel is especially suitable for electronic equipment required for highdisplay quality. Possible examples of such electronic equipment include,for example, personal computers and cellular phones.

In order to overcome the aforementioned problems, in the presentinvention, a method for manufacturing a color filter substrate includinga plurality of color filters for transmitting respective light withwavelengths corresponding to different colors, includes the steps offorming a reflection layer for reflecting light, which is provided witha translucent portion for transmitting light, on a substrate for holdinga liquid crystal between the substrate and other substrate, and forminga deep-color portion being superimposed on at least the translucentportion of the aforementioned reflection layer and a light-color portionhaving an optical density lower than that of the deep-color portion onthe aforementioned substrate and, thereby, forming the aforementionedplurality of color filters, each including the aforementioned deep-colorportion and light-color portion, and a light-shielding layer composed ofa laminate of at least the deep-color portions of the plurality of colorfilters on the aforementioned substrate.

According to the color filter substrate produced by this method formanufacture, the chroma of the transmitted light can be maintained at ahigh level without loss of the brightness of the reflected light by thereflection layer and, furthermore, the light-shielding property of thelight-shielding layer can be improved. In addition, since thelight-shielding layer can be produced at the same time with formation ofthe color filters, simplification of the manufacturing steps can beachieved compared with that in the case where the light-shielding layerand the color filters are formed in separate steps.

The present invention can also be used in the case where the colorfilters are arranged on a substrate different from the substrateprovided with the reflection layer. That is, a method for manufacturinga color filter substrate including a plurality of color filters fortransmitting respective light with wavelengths corresponding todifferent colors may include the step of forming a deep-color portion tobe superimposed on at least a translucent portion of a reflection layerand, a light-color portion having an optical density lower than that ofthe deep-color portion on the substrate for holding a liquid crystalbetween the substrate and other substrate including the aforementionedreflection layer for reflecting light, the reflection layer beingprovided with a translucent portion for transmitting light, and thereby,forming the aforementioned plurality of color filters, each includingthe aforementioned deep-color portion and light-color portion, and alight-shielding layer composed of a laminate of at least the deep-colorportions of the plurality of color filters. In this case, effectssimilar to those in the aforementioned method for manufacture can beachieved as well.

In these methods for manufacture, when the aforementioned deep-colorportion and light-color portion are formed, it is desirable to form thelight-shielding layer composed of a laminate of the deep-color portionsof the aforementioned plurality of color filters and the light-colorportion of at least one color filter of the aforementioned plurality ofcolor filters. According to this, the light-shielding property can befurther improved compared with that of the light-shielding layercomposed of only deep-color portions of the color filters.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing the configuration of a liquid crystaldisplay panel according to the first embodiment.

FIG. 2 is a perspective view showing the configuration of a key portionof the liquid crystal display panel shown in FIG. 1.

FIG. 3 is a sectional view showing a reflection layer, color filters,and a light-shielding layer under magnification.

FIG. 4 is a CIE chromaticity diagram showing the areas of colorreproduction region in the reflective display and the transmissivedisplay.

FIG. 5 is a sectional view showing a manufacturing process of the liquidcrystal display panel shown in FIG. 1.

FIG. 6 is a sectional view showing a manufacturing process of the liquidcrystal display panel shown in FIG. 1.

FIG. 7 is a sectional view showing the configuration of a liquid crystaldisplay panel according to the second embodiment.

FIG. 8 is a sectional view showing a reflection layer, color filters,and a light-shielding layer of a liquid crystal display panel accordingto a modified example of the present invention under magnification.

FIG. 9 is a sectional view showing a reflection layer, color filters,and a light-shielding layer of a liquid crystal display panel accordingto a modified example of the present invention under magnification.

FIG. 10 is a perspective view of the appearance configuration of apersonal computer as an example of electronic equipment to which theliquid crystal display panel according to the present invention isapplied.

FIG. 11 is a perspective view of the appearance configuration of acellular phone as an example of electronic equipment to which the liquidcrystal display panel according to the present invention is applied.

FIG. 12 is a sectional view showing the configuration of a conventionalliquid crystal display panel.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the present invention will be described below withreference to the drawings. The specification describes one or moreembodiments of the present invention. However, the specific examplesdisclosed herein is not intended to limit the present invention and,therefore, certain modifications can be performed within the scope ofthe present invention. Regarding each drawing described below, the scaleis varied on a layer or member basis in order that each layer or eachmember has a size capable of being identified in the drawing.

A. First Embodiment

The first embodiment will be described, in which the present inventionis applied to a semitransparent reflective liquid crystal display panelof an active matrix system. In the case exemplified below, a TFD (ThinFilm Diode) element, which is a two-terminal switching element, is usedas a switching element.

A-1: Configuration of Liquid Crystal Display Panel

FIG. 1 is a sectional view showing the configuration of a liquid crystaldisplay panel according to the present embodiment. As shown in FIG. 1,this liquid crystal display panel 1 has a configuration in which a firstsubstrate 10 and a second substrate 20 facing each other are adheredwith a sealing member 30 therebetween and, in addition, a liquid crystal40 of, for example, TN (Twisted Nematic) type and STN (Super TwistedNematic) type, is encapsulated in the region surrounded by both of thesubstrates and the sealing member 30. Hereafter, the first substrate 10side, when viewed from the liquid crystal 40, is denoted as “observationside”. This refers to the side of an observer visually identifying thedisplay by the liquid crystal display panel 1. On the other hand, thesecond substrate 20 side, when viewed from the liquid crystal 40, isdenoted as “backface side”.

The first substrate 10 and the second substrate 20 are plate-shapedmembers, for example, glass, quartz, and plastic, having a lighttransmission property. Polarizing plates 101 and 201 for polarizingincident light and phase difference plates 102 and 202 for compensatinginterference colors are adhered to the outer sides (the side opposite tothe liquid crystal 40) of the first substrate 10 and the secondsubstrate 20, respectively. A backlight unit (illumination apparatus) isarranged on the backface side of the liquid crystal display panel 1 inpractice, although not shown in the drawing.

FIG. 2 is a perspective view showing a key portion of the liquid crystaldisplay panel 1 under magnification. FIG. 1 corresponds a sectional viewof the section indicated by a line A-A′ shown in FIG. 2. In FIG. 2, inorder to prevent complication of the drawing, illustrations of thepolarizing plates 101 and 201 and the phase difference plates 102 and202 shown in FIG. 1 are omitted appropriately. As shown in FIG. 1 andFIG. 2, a plurality of pixel electrodes 11 arranged in the shape of amatrix and a plurality of scanning lines 12 extending in one directionin gap portions between individual pixel electrodes 11 are arranged onthe inner (liquid crystal 40 side) surface of the first substrate 10.Each pixel electrode 11 is a nearly rectangular electrode formed from atransparent conductive material, for example, ITO (Indium Tin Oxide).

As shown in FIG. 2, each pixel electrode 11 and the scanning line 12adjacent to the pixel electrode 11 are connected with a TFD element 13therebetween. Each TFD element 13 is a two-terminal switching elementhaving a non-linear current-voltage characteristic. As shown in FIG. 1,the surface of the first substrate 10 provided with the pixel electrodes11, scanning lines 12, and TFD elements 13 is covered with anorientation film 14 (not shown in FIG. 2). This orientation film 14 isan organic thin film made of polyimide, etc., and has been subjected toa rubbing treatment for regulating the orientation condition of theliquid crystal 40 when no voltage is applied.

On the other hand, a reflection layer 21, color filters 22 (22R, 22Q and22B), a light-shielding layer 23, an overcoat layer 24, data lines 25,and an orientation film 26 are arranged on the inner (liquid crystal 40side) surface of the second substrate 20 in that order when viewed fromthe second substrate 20 side. Among them, the overcoat layer 24 is alayer for flattening height differences formed by the color filters 22and the light-shielding layer 23, and is formed from, for example, anepoxy-based and an acryl-based resin material. As shown in FIG. 2, aplurality of data lines 25 are arranged on the surface of this overcoatlayer 24.

Each data line 25 is a belt-shaped electrode formed from a transparentconductive material, for example, ITO. Furthermore, each data line 25 isextended in the direction intersecting the aforementioned scanning line12, and is facing a plurality of pixel electrodes 11 arranged in a rowon the first substrate 10.

Under such a configuration, regarding the liquid crystal 40 held betweenthe first substrate 10 and the second substrate 20, the orientationdirection thereof varies by application of a voltage between a pixelelectrode 11 and the data line 25 facing each other. That is, as shownin FIG. 2, regions in which individual pixel electrodes 11 andindividual data lines 25 are facing each other are arranged in the shapeof a matrix, and each of them functions as a subpixel 7. In other words,it can be said that the subpixel 7 is a minimum unit of the region inwhich the orientation direction of the liquid crystal 40 varies inaccordance with application of a voltage.

The reflection layer 21 is formed from a single metal, for example,aluminum and silver, an alloy primarily containing these metals, or thelike, and is a thin film having a light reflection property. Incidentlight (for example, room illumination light and sunlight) from theobservation side upon the liquid crystal display panel 1 is reflected atthe surface of the reflection layer 21. This reflected light outgoes onthe observation side and is visually identified by the observer, so thatthe reflective display is performed. The inner surface of the secondsubstrate 20 has been roughened (not shown in the drawing), and ascattering structure has been formed on the surface of the reflectionlayer 21 incorporating this roughened surface.

In addition, as shown in FIG. 1 and FIG. 2, a translucent portion 211 isarranged in the neighborhood of the center portion of each subpixel 7 inthe reflection layer 21. The translucent portion 211 is an opening forallowing the light incident from the backface side to pass through uponthe observation side with respect to the liquid crystal display panel 1.That is, the irradiation light by the backlight unit outgoes on theobservation side through the translucent portion 211 of the reflectionlayer 21. This light is visually identified by the observer and,therefore, the transmissive display is realized.

The color filter 22 is a resin layer formed corresponding to eachsubpixel 7, and is colored any one of red (R), green (G), and blue (B)with a dye or pigment. That is, each of the color filters 22 (22R, 22G,and 22B) of respective colors selectively transmits light with awavelength corresponding to the color thereof. The exemplified case inthe present embodiment adopts a configuration (so-called stripearrangement) in which, as shown in FIG. 2, color filters 22 of the samecolor are arranged across a plurality of subpixels 7 aligned in a row inthe extension direction of the scanning lines 12.

FIG. 3 is a sectional view showing the reflection layer 21, the colorfilters 22, and the light-shielding layer 23 on the second substrate 20under magnification. As shown in FIG. 3, each of color filters 22 ofrespective colors is composed of a deep-color portion 221 and alight-color portion 222. That is, a red color filter 22R is composed ofa deep-color portion 221R and a light-color portion 222R, a green colorfilter 22G is composed of a deep-color portion 221G and a light-colorportion 222G, and a blue color filter 22B is composed of a deep-colorportion 221B and a light-color portion 222B. In each of the colorfilters 22 of respective colors, the deep-color portion 221 is arrangedwhile being superimposed on the translucent portion 211 of thereflection layer 21 in the subpixel 7. On the other hand, thelight-color portion 222 is arranged while being superimposed on theportion other than the translucent portion 211 of the reflection layer21 in the subpixel 7. When attention is focused on one color filter 22,the optical density of the deep-color portion 221 of the color filter 22is higher than the optical density of the light-color portion 222. Theoptical density refers to the ability to concentrate the wavelengthdistribution of light per unit thickness of the color filter. That is,when the optical density is high (large), the chroma of the transmittedlight becomes strong, and when the optical density is low (small), thechroma of the transmitted light becomes weak. The optical density of thecolor filter 22 is determined in accordance with, for example, aconcentration of a colorant (pigment or dye) blended into a transparentresin. That is, in the present embodiment, the colorant has been blendedinto the resin material constituting the deep-color portion 221 in onecolor filter 22 at a concentration higher than that in the resinmaterial constituting the light-color portion 222.

When the reflective display is performed in the liquid crystal displaypanel 1 according to the present invention, as indicated by a route R1shown in FIG. 3, incident light from the first substrate 10 side passesthrough the light-color portion 222 of the color filter 22, and reachesthe surface of the reflection layer 21. Subsequently, the lightreflected at the surface passes again through the light-color portion222, and outgoes on the observation side. Since the optical density ofthe light-color portion 222 is lower than that of the deep-color portion211, the brightness of the display when the reflective display isperformed can be maintained. On the other hand, when the transmissivedisplay is performed, as indicated by a route R2 shown in FIG. 3,incident light (irradiation light by a backlight unit) from the secondsubstrate 20 side passes through the deep-color portion 221 of the colorfilter 22 from the translucent portion 211 of the reflection layer 21,and outgoes on the observation side. Since the optical density of thedeep-color portion 221 is higher than that of the light-color portion222, the chroma when the transmissive display is performed can bemaintained at a high level. As described above, according to the presentembodiment, the chroma in the transmissive display can be improvedwithout loss of the brightness in the reflective display.

The light-shielding layer 23 is formed in the shape of a lattice whilebeing superimposed on the gap portions between individual subpixels 7arranged in the shape of a matrix, and performs a function of shieldingthe gaps between individual subpixels 7 from light. This light-shieldinglayer 23 has a configuration of a laminate of the deep-color portions221 of three color filters 22 of red, green, and blue as shown in FIG.3. Furthermore, in the present embodiment, the light-color portion 222Bof the blue color filter 22B is contained in the laminate in addition tothese deep-color portions 221. That is, the light-shielding layer 23 hasa configuration composed of a laminate of the light-color portion 222Bof the blue color filter 22B, the deep-color portion 221B of the bluecolor filter 22B, the deep-color portion 221R of the red color filter22R, and the deep-color portion 221G of the green color filter 22G inthat order when viewed from the surface of the second substrate 20.

Regarding the conventional configuration in which a single (that is, thedeep-color portion 221 and the light-color portion 222 are not divided)color filter 22 is arranged with respect to each subpixel 7 as shown inFIG. 12, a color filter 22 having a relatively low optical density mustbe used in order to ensure the brightness in the reflective display.Also, if the light-shielding layer 23 of a laminate of such colorfilters 22 has a low optical density, light-shielding between individualsubpixels 7 becomes inadequate and, therefore, adequate contrast ofdisplay may not be achieved. On the other hand, since thelight-shielding layer 23 in the present embodiment is composed of alaminate of the deep-color portions 221 having a high optical density ofthe color filters 22 of respective colors, the optical density of thetotal light-shielding layer 23 can be increased by a large degree.Consequently, according to the present embodiment, light-shieldingbetween individual subpixels 7 becomes adequate and, therefore,excellent contrast of the display is realized compared with that in theconventional configuration shown in FIG. 12.

Although room illumination light, sunlight, etc., are used in thereflective display, illumination light by a backlight unit is used inthe transmissive display. Consequently, in general, the quantity oflight used for displaying in the reflective display tends to be reducedremarkably compared with the quantity of light used for displaying inthe transmissive display. Even under such circumstances, the opticaldensities of the deep-color portion 221 and the light-color portion 222of each color filter 22 is desirably chosen in order that excellentdisplay quality can be maintained in both of the reflective display andthe transmissive display. Detailed description will be made below.

FIG. 4 is a CIE chromaticity diagram showing the area of colorreproduction region in the reflective display and the area of colorreproduction region in the transmissive display. When each color of thered, green, and blue is assumed to be displayed by the reflectivedisplay or the transmissive display, three points corresponding topractically displayed each color can be plotted on the CIE chromaticitydiagram. The region of the triangle having apexes of these three pointsis the color reproduction region. For example, as shown in FIG. 4, thearea of color reproduction region R of the reflective display becomes atriangular region having three apexes of a point Rr corresponding to reddisplay, a point Rg corresponding to green display, and a point Rbcorresponding to blue display. Similarly, the area of color reproductionregion T of the transmissive display becomes a triangular region havingthree apexes of a point Tr corresponding to red display, a point Tgcorresponding to green display, and a point Tb corresponding to bluedisplay.

It was discovered that when the area of color reproduction region T ofthe transmissive display was at least about 3.5 greater but less thanabout 5 times the area of color reproduction region R of the reflectivedisplay, excellent display quality could be maintained in both of thereflective display and the transmissive display. Consequently, it can besaid desirable that the optical densities of the deep-color portion 221and the light-color portion 222 of each color are chosen in order to setthe area ratio of the color reproduction region R to the colorreproduction region T at (color reproduction region R:color reproductionregion T)=(1:3.5 to 5) when the reflective display and the transmissivedisplay are performed in the liquid crystal display panel 1.

A-2: Manufacturing Process of Liquid Crystal Display Panel

A manufacturing process of the liquid crystal display panel 1 accordingto the present embodiment will be described with reference to FIG. 5 andFIG. 6. However, since each constituent on the first substrate 10 can bemanufactured using various known techniques, explanations thereof areomitted and, therefore, manufacturing processes of the reflection layer21, color filters 22, and light-shielding layer 23 on the secondsubstrate 20 will be primarily explained below.

A thin film of a metal having a light reflection property is formed by asputtering method, etc., in order to cover all over the second substrate20 surface which is to face the first substrate 10. Subsequently, theresulting thin film is patterned using photolithography and etchingtechnology and, therefore, as shown in FIG. 5(a), the reflection layer21 provided with translucent portions 211 (sometimes referred to hereinas “openings” or “light-transmitting portions”) in accordance withindividual subpixels 7 is formed. In order to form a scatteringstructure on the surface of the reflection layer 21, desirably, thesurface of the second substrate 20 is roughened in advance of formationof the reflection layer 21. Alternatively, a resin layer covering thesurface of the second substrate 20 may be formed in advance of formationof the reflection layer 21 and, thereafter, the surface of this resinlayer may be roughened.

Subsequently, color filters 22 of respective colors are formedsequentially on the surface of the second substrate 20 provided with thereflection layer 21. At this time, the blue color filter 22B, the redcolor filter 22R, and the green color filter 22G are assumed to beformed in that order. Regarding formation of the color filters 22 ofrespective colors, it is assumed that the light-color portion 222 isformed firstly, and then, the deep-color portion 221 is formed.

As shown in FIG. 5(b), a resin layer 61 colored blue is formed on allover the surface of the second substrate 20. This resin layer 61 becomesthe light-color portion 222B of the blue color filter 22B. Subsequently,the resulting resin layer 61 is partially removed using photolithographyand etching technology. Specifically, as shown in FIG. 5(c), the resinlayer 61 is removed except the portion not being superimposed on thetranslucent portion 211 of the blue subpixel 7B (that is, the portioncorresponding to the light-color portion 222B of the blue color filter22B) and the gap portions between individual subpixels 7 (that is, thelattice-shaped portion to be provided with the light-shielding layer23).

As shown in FIG. 5(d), a resin layer 62 colored blue is formed on allover the surface of the second substrate 20. This resin layer 62 becomesthe deep-color portion 221B of the blue color filter 22B. Consequently,the resin layer 62 contains a blue colorant at a concentration higherthan that in the resin layer 61 shown in FIG. 5(b).

Subsequently, the resin layer 62 is partially removed in a mannersimilar to that in the step shown in FIG. 5(c). That is, as shown inFIG. 5(e), the resin layer 62 is removed except the portion beingsuperimposed on the translucent portion 211 of the blue subpixel 7B(that is, the portion corresponding to the deep-color portion 221B ofthe blue color filter 22B) and the gap portions between individualsubpixels 7 (that is, the portion to be provided with thelight-shielding layer 23). According to the aforementioned steps, theblue color filter 22B composed of the deep-color portion 221B beingsuperimposed on the translucent portion 211 of the reflection layer 21and the light-color portion 222B having an optical density lower thanthe deep-color portion 221B is formed and, in addition, a part of thelight-shielding layer 23 which is a laminate of the deep-color portion221B and the light-color portion 222B is formed.

Then, a series of steps shown in FIG. 5(b) to FIG. 5(e) are repeatedwith respect to red and green as well. That is, a resin layer coloredred is formed on the surface of the second substrate 20. Subsequently,this resin is partially removed and, therefore, as shown in FIG. 6(f),the light-color portion 222R of the red color filter 22R is formed.Although the portion corresponding to the light-shielding layer 23 wasnot removed regarding the resin layer 61 for forming the bluelight-color portion 222B, regarding the resin layer for forming red andgreen, which is described later, light-color portions 222, the portionscorresponding to this light-shielding layer 23 are removed.

After a resin layer containing a colorant at a concentration higher thanthat in the light-color portion 222R is formed on the second substrate20, this resin layer is partially removed and, therefore, as shown inFIG. 6(g), the deep-color portion 221R of the red color filter 22R andthe deep-color portion 221R constituting the light-shielding layer 23are formed. According to the steps shown in FIGS. 6(f) and (g), the redcolor filter 22R composed of the deep-color portion 221R and thelight-color portion 222R is formed.

Subsequently, in a procedure similar to that shown in FIGS. 5(b) and(c), as shown in FIG. 6(h), the light-color portion 222G of the greencolor filter 22G is formed and, in addition, in a procedure similar tothat shown in FIGS. 5(d) and (e), as shown in FIG. 6(i), the deep-colorportions 221G of the green color filter 22G are formed. This deep-colorportion 221G is installed on the portion corresponding to thelight-shielding layer 23. As a result, the green color filter 22Gcomposed of the deep-color portion 221G and the light-color portion 222Gis formed and, in addition, the light-shielding layer 23 which iscomposed of a laminate of the blue light-color portion 222B, the bluedeep-color portion 221B, the red deep-color portion 221R, and the greendeep-color portion 221G is formed.

Subsequently, as shown in FIG. 6(j), an epoxy-based or acryl-based resinmaterial is applied by coating in order to cover all over the surface ofthe second substrate 20 provided with the reflection layer 21, colorfilters 22, and the light-shielding layer 23, firing is performed and,therefore, the overcoat layer 24 is formed. Furthermore, the data lines25 made of ITO are formed on the surface of this overcoat layer 24 and,in addition, the orientation film 26 is formed in order to cover thesedata lines 25.

Up to this point, the manufacturing process of each constituent on thesecond substrate 20 has been described. Then, the second substrate 20produced by this manufacturing process and the first substrate 10provided with the pixel electrodes 11 and the scanning lines 12 areadhered with each other with the sealing member 30 in the condition thatthe surfaces provided with electrodes are faced each other. The liquidcrystal 40 is encapsulated in the region surrounded by both of thesubstrates and the sealing member 30 and, therefore, the liquid crystaldisplay panel 1 shown in FIG. 1 is produced.

According to the manufacturing method described above, thelight-shielding layer 23 can be formed simultaneously in the step offorming the color filters 22. Consequently, simplification of themanufacturing steps and reduction in the manufacturing cost can beachieved compared with those in the case where the color filter 22 andthe light-shielding layer 23 are formed in separate steps.

Second Embodiment

Next, the configuration of a liquid crystal display panel according tothe second embodiment of the present invention will be described withreference to FIG. 7. Among the constituents shown in FIG. 7, commonconstituents with the liquid crystal display panel according to thefirst embodiment shown in the aforementioned FIG. 1 are indicated by thesame reference numerals.

In the aforementioned embodiment, the configuration in which the colorfilters 22 and the light-shielding layer 23 are arranged on the surfaceof the second substrate 20 located on the backface side was exemplified.On the other hand, in a liquid crystal display panel 2 according to thepresent embodiment, as shown in FIG. 7, the color filters 22, thelight-shielding layer 23, and the overcoat layer 24 are arranged on thesurface of the first substrate 10 located on the observation side.

That is, the color filters 22 (22R, 22G; and 22B), each being coloredany one of red, green, and blue, are arranged on the inner surface ofthe first substrate 10. The color filter 22 in the present embodimenthas a configuration similar to that of the color filter 22 shown in theaforementioned first substrate, and is composed of the deep-colorportion 221 being superimposed on the translucent portion 211 of thereflection layer 21 and the light-color portion 222 having an opticaldensity lower than the deep-color portion 221. The light-shielding layer23 has a configuration composed of a laminate of the deep-color portions221 of at least each of red, green, and blue color filters 22. However,in the present embodiment, in a manner similar to that in theaforementioned first embodiment, the light-color portion 222B of theblue color filter 22B is also contained in the laminate in addition tothe deep-color portions 221 of each of the colors. The overcoat layer 24is arranged in order to cover the surface of the first substrate 10provided with the color filters 22 and the light-shielding layer 23. Thepixel electrodes 11, the scanning lines 12, and the TFD elements 13 arearranged on the surface of the overcoat layer 24, and the orientationfilm 14 is arranged in order to cover the overcoat layer 24. The colorfilters 22 and the light-shielding layer 23 of the liquid crystaldisplay panel 2 according to the present embodiment are manufacturedthrough a manufacturing process similar to that described in the firstembodiment using FIG. 5 and FIG. 6 as examples.

On the other hand, the reflection layer 21 arranged on the inner surfaceof the second substrate 20 is covered with an insulation layer 27 madeof a resin material, etc. The data lines 25 and the orientation film 26are arranged on the surface of this insulation layer 27.

Effects similar to those in the aforementioned first embodiment can alsobe achieved by the aforementioned configuration in which the firstsubstrate 10 located on the observation side is provided with the colorfilters 22 and the light-shielding layer 23 and, in addition, the secondsubstrate 20 located on the backface side is provided with thereflection layer 21. That is, the color filter substrate according tothe present invention refers to a substrate provided with the colorfilters 22 and the light-shielding layer 23 regardless of whether thesubstrate is arranged on the observation side or backface side.

MODIFIED EXAMPLE

The aforementioned embodiments are no more than an exemplification, andvarious modifications can be applied to the aforementioned embodimentswithin the purport of the present invention. It is considered thatmodified examples include, for example, the following.

C-1. Modified Example 1

In the aforementioned embodiment, the light-shielding layer 23 wasconfigured as a laminate of the deep-color portions 221 of each of red,green, and blue color filters 22 and the light-color portion 222B of theblue color filter 22B. However, the lamination structure of thelight-shielding layer 23 is not limited to this. For example, as shownin FIG. 8, the light-shielding layer 23 may be configured as a laminateof both of the deep-color portions 221 and the light-color portions 222of red, green, and blue color filters 22. That is, the light-shieldinglayer 23 shown in FIG. 8 has a configuration of a six-layer laminatecomposed of the light-color portion 222B of the blue color filter 22B,the deep-color portion 221B of the blue color filter 22B, thelight-color portion 222R of the red color filter 22R, the deep-colorportion 221R of the red color filter 22R, the light-color portion 222Gof the green color filter 22G, and the deep-color portion 221G of thegreen color filter 22G in that order when viewed from the secondsubstrate 20.

As described above, when the light-shielding layer 23 is formed bylaminating not only the deep-color portions 221 of the color filters 22,but also the light-color portions 222, the optical density of thelight-shielding layer 23 can be maintained at a high level and,therefore, further excellent contrast of the display can be achieved.

As shown in FIG. 9, the light-shielding layer 23 may be configured as alaminate of only the deep-color portions 221 of the red, green, and bluecolor filters 22. That is, the light-shielding layer 23 does notnecessarily include the light-color portion 222 of any one of the colorfilters 22. The light-shielding layer 23 shown in FIG. 9 has aconfiguration of a three-layer laminate composed of the deep-colorportion 221B of the blue color filter 22B, the deep-color portion 221Rof the red color filter 22R, and the deep-color portion 221G of thegreen color filter 22G in that order when viewed from the secondsubstrate 20. When the light-shielding layer 23 is formed by laminatingonly the deep-color portions of the color filters 22 as described above,the thickness of the light-shielding layer 23 can be reduced.

As shown in this modified example, in the present invention, it isessential that the deep-color portions 221 of the color filters 22 of atleast a plurality of colors (red, green, and blue) are laminated and,therefore, the light-shielding layer 23 is formed.

C-2 Modified Example 2

In the aforementioned embodiment, the case where the color filters 22were formed in order of blue→red→green and, in addition, the colorfilter 22 of each of the colors was formed in order of light-colorportion 222→deep-color portion 221 was exemplified. However, the orderof formation of the color filters 22 of each of the colors and thedeep-color portion 221 and the light-color portion 222 of each colorfilter 22 are not limited to them. For example, the deep-color portions221 of each of the red, green, and blue color filters 22 may be formedand, thereafter, the light-color portions 222 of the color filters 22 ofeach of these colors may be formed. Consequently, the order of theindividual layers constituting the light-shielding layer 23 is notlimited to that shown in each of the aforementioned embodiments and amodified example.

C-3 Modified Example 3

In each of the aforementioned embodiments, the case where the deep-colorportion 221 was formed in the region being superimposed on thetranslucent portion 211 of the reflection layer 21 in the subpixel 7,while the light-color portion 222 was formed in the region other thanthat region was exemplified. However, the deep-color portion 221 mayreach the region other than the region being superimposed on thetranslucent portion 211. That is, the deep-color portion 221 may beformed over the region being superimposed on the translucent portion 211of the reflection layer 21 in the subpixel 7 and a part of the regionnot being superimposed thereon, while the light-color portion 222 may beformed in the region other than that region. In the present invention,it is essential that the deep-color portion 221 is arranged in order tobe superimposed on at least the translucent portion 211 of thereflection layer 21.

C-4 Modified Example 4

In each of the aforementioned embodiments, the liquid crystal displaypanel of the active matrix system using the TFD element 13, which was atwo-terminal switching element, was exemplified. However, as a matter ofcourse, the present invention can be applied to a liquid crystal displaypanel using a three-terminal switching element exemplified by the TFT(Thin Film Transistor) element and a liquid crystal display panel of thepassive matrix system having no switching element. In each of theaforementioned embodiments, the case where a stripe arrangement in whichcolor filters 22 having the same color were arranged in a row wasadopted was exemplified. However, in addition to this, a mosaicarrangement and a delta arrangement can also be adopted as the mode ofthe arrangement of the color filters 22. Accordingly, as long as a colorfilter substrate is provided with the color filters 22 and thelight-shielding layer 23, and a liquid crystal display panel uses thiscolor filter substrate, the present invention can be applied regardlessof modes with respect to other constituents.

Electronic Equipment

Next, electronic equipment using the liquid crystal display panelaccording to the present invention will be described.

D-1. Mobile Type Computer

An example, in which the liquid crystal display panel according to thepresent invention is applied to the display portion of a portablepersonal computer (so-called notebook personal computer), will bedescribed. FIG. 10 is a perspective view showing the configuration ofthis personal computer. As shown in FIG. 10, the personal computer 91 isprovided with a body portion 912 including a keyboard 911, and a displayportion 913, to which the liquid crystal display panel according to thepresent invention is applied.

D-2. Cellular Phone

An example, in which the liquid crystal display panel according to thepresent invention is applied to the display portion of a cellular phone,will be described. FIG. 11 is a perspective view showing theconfiguration of this cellular phone. As shown in FIG. 11, a cellularphone 92 is provided with a plurality of operation buttons 921 and, inaddition, an earpiece 922, a mouthpiece 923 and, furthermore, a displayportion 924, to which the liquid crystal display panel according to thepresent invention is applied.

Examples of electronic equipment, to which the liquid crystal displaypanel according to the present invention can be applied, include, forexample, liquid crystal televisions, viewfinder type andmonitor-direct-view type videotape recorders, car navigation devices,pagers, electronic notepads, desk-top calculators, word processors, workstations, videophones, POS terminals, and digital steel cameras, inaddition to the personal computer shown in FIG. 10 and the cellularphone shown in FIG. 11.

As described above, according to the present invention, the chroma inthe transmissive display can be improved without loss of the brightnessin the reflective display.

1. A color filter substrate having a first portion where a reflectionlayer is arranged and a second portion for transmitting light, the colorfilter substrate comprising: a substrate for holding a liquid crystalbetween the substrate and another substrate; a plurality of colorfilters on the substrate, the color filters transmitting light with wavelengths of different colors, each color filter having a deep-colorportion having a given optical density and a light-color portion of alower optical density, the deep-color portion being located in thesecond portion and the light-color portion being located in the firstportion; and a light-shielding layer formed of a laminate structure ofthe color filters, the laminate structure including the deep-colorportion of the color filters, the deep-color portion of the colorfilters in the light-shielding layer being in a non-overlappingcondition with the corresponding light-color portion of the colorfilters, the corresponding light-color portion of the color filtersbeing adjacent to the light-shielding layer and being located in thefirst portion.
 2. A color filter substrate having a first portion wherea reflection layer is arranged and a second portion for transmittinglight, the color filter substrate comprising: a substrate for holding aliquid crystal between the substrate and another substrate provided witha reflection layer for reflecting light; a plurality of color filterswhich are arranged on the substrate, the color filters transmittingrespective light with wavelengths corresponding to different colors, andeach of the color filters including a deep-color portion beingsuperimposed on at least the second portion and a light-color portionhaving an optical density lower than an optical density of thedeep-color portion being located on the reflection portion; and alight-shielding layer formed of a laminate structure of the colorfilters, the laminate structure including the deep-color portion of thecolor filters, the deep-color portion of the color filters in thelight-shielding layer being in a non-overlapping condition with thecorresponding light-color portion of the color filters, thecorresponding light-color portion of the color filters being adjacent tothe light-shielding layer and being located in the first portion.
 3. Acolor filter substrate having a first portion where a reflection layeris arranged and a second portion for transmitting light, the colorfilter substrate comprising: a substrate for holding a liquid crystalbetween the substrate and another substrate; a plurality of colorfilters on the substrate, the color filters transmitting light withwavelengths of different colors, each color filter having a deep-colorportion having a given optical density and a light-color portion of alower optical density, the deep-color portion being located in thesecond portion and the light-color portion being located in the firstportion; and a light-shielding layer formed of a laminate structure ofthe color filters, the laminate structure including the deep-colorportion of one of the color filters and the light-color portion of oneof the color filters, the light-color portion of the color filters beingadjacent to the light-shielding layer and being located in the firstportion, a second layer of the light-shielding layer from the substrateis the deep-color portion of the one of the color filters.
 4. A colorfilter substrate having a first portion where a reflection layer isarranged and a second portion for transmitting light, the color filtersubstrate comprising: a substrate for holding a liquid crystal betweenthe substrate and another substrate provided with a reflection layer forreflecting light; a plurality of color filters arranged on thesubstrate, the color filters transmitting respective light withwavelengths corresponding to different colors, and each of the colorfilters including a deep-color portion being superimposed on at leastthe second portion and a light-color portion having an optical densitylower than an optical density of the deep-color portion being located onthe reflection portion, the light-color portion being located in thefirst portion; and a light-shielding layer formed of a laminatestructure of the color filters, the laminate structure including thedeep-color portion of one of the color filters and the light-colorportion of one of the color filters, the light-color portion of thecolor filters being adjacent to the light-shielding layer and beinglocated in the first portion, a second layer of the light-shieldinglayer from the substrate is the deep-color portion of the one of thecolor filters.
 5. A liquid crystal display panel including a liquidcrystal between a first substrate and a second substrate facing eachother, the liquid crystal display panel having a first portion where areflection layer is arranged and a second portion for transmittinglight, the liquid crystal display panel comprising: a reflection layerfor reflecting the light, the reflection layer being arranged on thesecond substrate; a plurality of color filters which are arranged on anobservation side with respect to the reflection layer, the color filterstransmitting respective light with wavelengths corresponding todifferent colors, and each of the color filters including a deep-colorportion being superimposed on at least the second portion and alight-color portion having an optical density lower than an opticaldensity of the deep-color portion, the light-color portion being locatedin the first portion; and a light-shielding layer formed of a laminatestructure of the color filters, the laminate structure including thedeep-color portion of the color filters, the deep-color portion of thecolor filters in the light-shielding layer being in a non-overlappingcondition with the corresponding light-color portion of the colorfilters, the corresponding light-color portion of the color filtersbeing adjacent to the light-shielding layer and being located in thefirst portion.
 6. A liquid crystal display panel including a liquidcrystal between a first substrate and a second substrate facing eachother, the liquid crystal display panel having a first portion where areflection layer is arranged and a second portion for transmittinglight, the liquid crystal display panel comprising: a reflection layerfor reflecting the light, the reflection layer being arranged on thesecond substrate and being provided with a second portion; a pluralityof color filters arranged on the observation side with respect to thereflection layer, the color filters transmitting respective light withwavelengths corresponding to different colors, and each of the colorfilters including a deep-color portion being superimposed on at leastthe second portion and a light-color portion having an optical densitylower than an optical density of the deep-color portion, the light-colorportion being located in the first portion; and a light-shielding layerformed of a laminate structure of the color filters, the laminatestructure including the deep-color portion of one of the color filtersand the light-color portion of one of the color filters, the light-colorportion of the color filters being adjacent to the light-shielding layerand being located in the first portion, a second layer of thelight-shielding layer from the substrate is the deep-color portion ofthe one of the color filters.
 7. The liquid crystal display panel ofclaim 5 in combination with electronic equipment.
 8. The liquid crystaldisplay panel of claim 6 in combination with electronic equipment.